This invention relates to a pneumatic device for detecting continuously the hydrometric level of a water column (a well, a tank, a gathering basin and so on), and for operating automatically a manufacturing machine (as for instance, a motor-driven pump) in correspondence with two values of minimum and maximum level that are set forth previously.
In plants for rising and conveying a liquid, and in particular water, which are fed by a well, a reservoir, a tank, a basin or a tub or by any other system for holding water, it is very important to know the level of the available liquid at any time in order to operate in a suitable and safe way the manufacturing machine, which generally consists in a motor-driven pump that is to carry out the rising of water and/or the conveying of the same.
When plants of heights of a few meters and wells of diameters larger than about 50 cm are dealt with, such problem has no particular bearing and the intervention of the motor-driven pump is caused to occur on direct command, by a float switch that is free to operate because of the wide space available.
In the case of plants of diameters from 15 cm to about 50 cm and of heights of some ten meters, said systems are unsuitable or poorly reliable because of the reduced space, and anyway they do not allow the value of the level or of the water volume available to be known directly as shown on a control panel board placed at a distance from the well, nor do they allow the most suitable drawing of water to be programmed each time automatically and said drawing to be stopped when the water level reaches a point below a minimum value which has been set forth previously directly from the control board of the motor-driven pump.
The object of the present invention consists in the solution to the problem outlined above, by means of a device that allows the hydrometric level of a water column to be detected continuously, and that allows a motor-driven pump to be put automatically in operation in correspondence with two values set forth previously: i.e., a maximum and a minimum value, at which the motor-driven pump is started or stopped.
In the case of a well, the starting of the motor-driven pump is operated automatically when a maximum level previously set forth is attained, and the stop of the motor-driven pump is operated automatically at the very moment when the water column goes below the minimum level which is set forth previously on the control board. As it is possible to detect at any time the value of said level, it is evident that the device in question allows the amount of the water drawn by the plant to be adjusted according to the operative procedures which are thought of as the most suitable.
According to the present invention, a device is provided which comprises, in combination, a tubular probe dipped into the liquid column, a pair of pneumatic detectors of the minimum and maximum level, which are operated by the air pressure occurring within said probe, and a command and signaling unit or assembly that causes the operation and the stop of a motor-driven pump, respectively, when the maximum and the minimum hydrometric level of the water column are reached.
Again according to the present invention, the pneumatic detector of maximum level is associated to a system capable of transducing the air pressure within the detector itself into a signal which is indicative of the hydrometric level, said level being variable between said two maximum and minimum values.
This invention will be disclosed in the following with reference to the enclosed drawings, which represent just for illustrative and not for limitative purposes a preferred kind of embodiment of the invention itself .